PHPMailer SMTP localhost, certificate error

Question

We use PHPMailer. The server is configured to use the local SMTP. So, the general PHPMailer commando looks like this:

$mail = new PHPMailer();
$mail->From = '[email protected]';
$mail->Host = 'localhost';
$mail->IsSMTP();
...

Since PHP5.6, this doesn't work anymore, because the certificate does not match. We get the following error:

Warning: stream_socket_enable_crypto(): Peer certificate CN='*.thisvps.com' did not match expected CN='localhost' in /ho...PHPMailer_latest/class.smtp.php

I can suppress this error using:

$this->smtpConnect([
   'ssl' => [
       'verify_peer' => false,
       'verify_peer_name' => false,
       'allow_self_signed' => true
   ]
]);

But, is that the correct way to go? I'm not a big fan of suppressing errors;). Or maybe there is an error in our configuration?

Version info: PHP 5.6.30, PHPMailer: 5.2.21

Any suggestion are welcome, thanks in advance!

Answer 1

It's odd that you're getting that cert from the server if it's not something you have configured. It could be down to your ISP redirecting your traffic, though I wouldn't expect that to affect localhost.

You can turn off encryption altogether (it's safe to localhost as there's no external network traffic) with $mail->SMTPSecure = false;, though you may need to also set $mail->SMTPAutoTLS = false; to prevent it being re-enabled automatically if your server advertises STARTTLS.

Alternatively, this host presumably has a hostname in the thisvps.com domain that you could use, and then the name would match the cert.